1. Barometers come in many forms. As weather forecasting
instruments go, barometers predict rain or shine. Rising pressure
usually indicates sunny skies, while falling pressure on a barometer means a good
chance of rain.
2. Two common types of barometric weather instruments are the mercury
barometer and the aneroid barometer. Most of the ones here are aneroid
barometers, because they do not use liquid to attain a reading.
3. Barometric pressure can be read in a number of ways by weather
instruments. The most common of these is in inches of mercury (often
transcribed to a dial or digital readout), or in millibars.
4. Digital barometers are perfect for going out into the field. Many
digital barometers can retain readings over the previous day, and you
can compare hourly readings, too.
5. When using your barometer as a forecasting weather instrument, you
should know that the absolute reading at any given time is not the most
important aspect. Rather, the rate of change on the barometer.
